me.hao0.common.util

Class Preconditions

java.lang.Object

me.hao0.common.util.Preconditions

public final class Preconditions
extends Object

Method Summary

Methods

Modifier and Type	Method and Description
static void	checkArgument(boolean expression) Ensures the truth of an expression involving one or more parameters to the calling method.
static void	checkArgument(boolean expression, Object errorMessage) Ensures the truth of an expression involving one or more parameters to the calling method.
static void	checkArgument(boolean expression, String errorMessageTemplate, Object... errorMessageArgs) Ensures the truth of an expression involving one or more parameters to the calling method.
static int	checkElementIndex(int index, int size) Ensures that index specifies a valid element in an array, list or string of size size.
static int	checkElementIndex(int index, int size, String desc) Ensures that index specifies a valid element in an array, list or string of size size.
static void	checkNegative(Number number, String field)
static <T> T	checkNotNull(T reference) Ensures that an object reference passed as a parameter to the calling method is not null.
static <T> T	checkNotNull(T reference, Object errorMessage) Ensures that an object reference passed as a parameter to the calling method is not null.
static <T> T	checkNotNull(T reference, String errorMessageTemplate, Object... errorMessageArgs) Ensures that an object reference passed as a parameter to the calling method is not null.
static void	checkNotNullAndEmpty(Collection<?> checking, String field)
static void	checkNotNullAndEmpty(String checking, String field)
static int	checkPositionIndex(int index, int size) Ensures that index specifies a valid position in an array, list or string of size size.
static int	checkPositionIndex(int index, int size, String desc) Ensures that index specifies a valid position in an array, list or string of size size.
static void	checkPositionIndexes(int start, int end, int size) Ensures that start and end specify a valid positions in an array, list or string of size size, and are in order.
static void	checkPositive(Number number, String field)
static void	checkState(boolean expression) Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.
static void	checkState(boolean expression, Object errorMessage) Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.
static void	checkState(boolean expression, String errorMessageTemplate, Object... errorMessageArgs) Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

checkArgument

public static void checkArgument(boolean expression)

Ensures the truth of an expression involving one or more parameters to the calling method.

Parameters:

expression - a boolean expression

Throws:

IllegalArgumentException - if expression is false

checkArgument

public static void checkArgument(boolean expression,
                 Object errorMessage)

Ensures the truth of an expression involving one or more parameters to the calling method.

Parameters:

expression - a boolean expression

errorMessage - the exception message to use if the check fails; will be converted to a string using String.valueOf(Object)

Throws:

IllegalArgumentException - if expression is false

checkArgument

public static void checkArgument(boolean expression,
                 String errorMessageTemplate,
                 Object... errorMessageArgs)

Ensures the truth of an expression involving one or more parameters to the calling method.

Parameters:

expression - a boolean expression

errorMessageTemplate - a template for the exception message should the check fail. The message is formed by replacing each %s placeholder in the template with an argument. These are matched by position - the first %s gets errorMessageArgs[0], etc. Unmatched arguments will be appended to the formatted message in square braces. Unmatched placeholders will be left as-is.

errorMessageArgs - the arguments to be substituted into the message template. Arguments are converted to strings using String.valueOf(Object).

Throws:

IllegalArgumentException - if expression is false

NullPointerException - if the check fails and either errorMessageTemplate or errorMessageArgs is null (don't let this happen)

checkState

public static void checkState(boolean expression)

Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.

Parameters:

expression - a boolean expression

Throws:

IllegalStateException - if expression is false

checkState

public static void checkState(boolean expression,
              Object errorMessage)

Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.

Parameters:

expression - a boolean expression

errorMessage - the exception message to use if the check fails; will be converted to a string using String.valueOf(Object)

Throws:

IllegalStateException - if expression is false

checkState

public static void checkState(boolean expression,
              String errorMessageTemplate,
              Object... errorMessageArgs)

Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.

Parameters:

expression - a boolean expression

errorMessageTemplate - a template for the exception message should the check fail. The message is formed by replacing each %s placeholder in the template with an argument. These are matched by position - the first %s gets errorMessageArgs[0], etc. Unmatched arguments will be appended to the formatted message in square braces. Unmatched placeholders will be left as-is.

errorMessageArgs - the arguments to be substituted into the message template. Arguments are converted to strings using String.valueOf(Object).

Throws:

IllegalStateException - if expression is false

NullPointerException - if the check fails and either errorMessageTemplate or errorMessageArgs is null (don't let this happen)

checkNotNull

public static <T> T checkNotNull(T reference)

Ensures that an object reference passed as a parameter to the calling method is not null.

Type Parameters:

T - generic type

Parameters:

reference - an object reference

Returns:

the non-null reference that was validated

Throws:

NullPointerException - if reference is null

checkNotNull

public static <T> T checkNotNull(T reference,
                 Object errorMessage)

Ensures that an object reference passed as a parameter to the calling method is not null.

Type Parameters:

T - generic type

Parameters:

reference - an object reference

errorMessage - the exception message to use if the check fails; will be converted to a string using String.valueOf(Object)

Returns:

the non-null reference that was validated

Throws:

NullPointerException - if reference is null

checkNotNull

public static <T> T checkNotNull(T reference,
                 String errorMessageTemplate,
                 Object... errorMessageArgs)

Ensures that an object reference passed as a parameter to the calling method is not null.

Type Parameters:

T - generic type

Parameters:

reference - an object reference

errorMessageTemplate - a template for the exception message should the check fail. The message is formed by replacing each %s placeholder in the template with an argument. These are matched by position - the first %s gets errorMessageArgs[0], etc. Unmatched arguments will be appended to the formatted message in square braces. Unmatched placeholders will be left as-is.

errorMessageArgs - the arguments to be substituted into the message template. Arguments are converted to strings using String.valueOf(Object).

Returns:

the non-null reference that was validated

Throws:

NullPointerException - if reference is null

checkElementIndex

public static int checkElementIndex(int index,
                    int size)

Ensures that index specifies a valid element in an array, list or string of size size. An element index may range from zero, inclusive, to size, exclusive.

Parameters:

index - a user-supplied index identifying an element of an array, list or string

size - the size of that array, list or string

Returns:

the value of index

Throws:

IndexOutOfBoundsException - if index is negative or is not less than size

IllegalArgumentException - if size is negative

checkElementIndex

public static int checkElementIndex(int index,
                    int size,
                    String desc)

Ensures that index specifies a valid element in an array, list or string of size size. An element index may range from zero, inclusive, to size, exclusive.

Parameters:

index - a user-supplied index identifying an element of an array, list or string

size - the size of that array, list or string

desc - the text to use to describe this index in an error message

Returns:

the value of index

Throws:

IndexOutOfBoundsException - if index is negative or is not less than size

IllegalArgumentException - if size is negative

checkPositionIndex

public static int checkPositionIndex(int index,
                     int size)

Ensures that index specifies a valid position in an array, list or string of size size. A position index may range from zero to size, inclusive.

Parameters:

index - a user-supplied index identifying a position in an array, list or string

size - the size of that array, list or string

Returns:

the value of index

Throws:

IndexOutOfBoundsException - if index is negative or is greater than size

IllegalArgumentException - if size is negative

checkPositionIndex

public static int checkPositionIndex(int index,
                     int size,
                     String desc)

Ensures that index specifies a valid position in an array, list or string of size size. A position index may range from zero to size, inclusive.

Parameters:

index - a user-supplied index identifying a position in an array, list or string

size - the size of that array, list or string

desc - the text to use to describe this index in an error message

Returns:

the value of index

Throws:

IndexOutOfBoundsException - if index is negative or is greater than size

IllegalArgumentException - if size is negative

checkPositionIndexes

public static void checkPositionIndexes(int start,
                        int end,
                        int size)

Ensures that start and end specify a valid positions in an array, list or string of size size, and are in order. A position index may range from zero to size, inclusive.

Parameters:

start - a user-supplied index identifying a starting position in an array, list or string

end - a user-supplied index identifying a ending position in an array, list or string

size - the size of that array, list or string

Throws:

IndexOutOfBoundsException - if either index is negative or is greater than size, or if end is less than start

IllegalArgumentException - if size is negative

checkNotNullAndEmpty

public static void checkNotNullAndEmpty(String checking,
                        String field)

checkNotNullAndEmpty

public static void checkNotNullAndEmpty(Collection<?> checking,
                        String field)

checkPositive

public static void checkPositive(Number number,
                 String field)

checkNegative

public static void checkNegative(Number number,
                 String field)